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 Flavonoids are synthesized by the phenylpropanoid

metabolic pathway in which the amino

acid phenylalanine is used to produce 4-coumaroyl-

CoA.

 This can be combined with malonyl-CoA to yield the true

backbone of flavonoids, a group of compounds

called chalcones, which contain two phenyl rings.

Conjugate ring-closure of chalcones results in the

familiar form of flavonoids, the three-ringed structure of

a flavone. The metabolic pathway continues through a

series of enzymatic modifications to

yield flavanones → dihydroflavonols → anthocyanins.

Along this pathway, many products can be formed,

including the flavonols, flavan-3-

ols, proanthocyanidins (tannins) and a host of other

various polyphenolics.

Biosynthesis of Flavonoids